1. Field Of The Invention
The present invention relates generally to aquatic propulsion systems and more specifically to a propulsion system, located in the front of the submarine, for a nuclear powered submarine. It may also be used for torpedo propulsion.
2. Problems In The Art
Currently, underwater vehicles, such as nuclear powered submarines, are propelled through the water using a propeller based propulsion system located at the stern of the vehicle. Drag forces acting on the vehicle cause the water around the vehicle to become displaced and turbulent in nature. Propeller based propulsion systems located at the stern are forced to push the submarine against this resultant turbulent water. This leads to decreased efficiency and a lower overall thrust. Further, current propeller based propulsion systems increase a submatine""s noise which may aid others in detecting the submarine.
FIG. 1 depicts pictorially the general arrangement of a conventional Sea Wolf class submarine 10. A propeller 18 is located at the stern 16 of the submarine 10. Propeller 18 is driven by an axle 20 that is connected to a steam turbine 22 that can be powered by a nuclear reactor. A transmission 24 converts rotational power of axle 20 into a desired rotational speed for the propeller 10. Alternatively, an electric motor may be used for low noise emission.
A conventional configuration requires a propulsion system to essentially push the submarine through the water, causing drag and displacing or, the water in front of the submarine. This limits efficiency, stability, and speed.
Surface water vehicles also typically rely on a propeller fan either by an inboard or outboard stern positioned engine for propulsion. Similarly, this stern drive requires the vehicle to be pushed through the water, causing drag and displacing all the water in front of the vehicle, which limits efficiency, stability, and speed.
Attempts have been made to address these problems for surface water vehicles. U.S. Pat. No. 5,634,419 to Cymara discloses what is called a xe2x80x9cfront-drive boatxe2x80x9d wherein a propeller propulsion system is located towards the stern (bow) of the boat which is claimed to increase stability of the boat.
U.S. Pat. No. 4,680,017 to Eller, entitled xe2x80x9cmotorboat propeller guard for improved performancexe2x80x9d, places a propeller inside a housing, with grids configured to attempt to direct propelled water rearwardly for improved performance.
Herein incorporated by reference, U.S. Pat. Nos. 5,383,801 to Chas, 4,902,254 to Chas, 4,831,297 to Taylor et al., disclose propulsion systems for over the watercraft that adopt jet engine principles to attempt to increase propulsion.
Another propeller based propulsion systems is U.S. Pat. No. 5,252,875 to Veronesi, et al. herein incorporated by reference. Many of the above patents resemble a jet engine in appearance and further resemble a jet engine in the manner in which they are attached to a vehicle; i.e. they hang down from the craft.
Therefore, although attempts have been made to apply jet engine type principles to above water craft, and attempts have been made to increase stability of propulsion of over the water crafts, submarine propulsion systems have remained relatively the same, utilizing stern drive propeller fan propulsion.
There is therefore a need for a submarine propulsion system, which avoids these and other problems in the art.
A general feature of the present invention is the provision of propulsion system for a submarine, which overcomes the problems found in the prior art.
Further feature of the present invention is a propulsion system for a submarine, which is more stable.
Further feature of the present invention is the provision of a propulsion system for a submarine, which is more efficient.
For further feature of the present invention is the provision of a propulsion system for a submarine which is fast.
A further feature of the present invention is the provision of a propulsion system for a submarine, which produces high thrust.
Another feature of the present invention is the provision of a propulsion system for a submarine, which may be maintained while underwater.
A still further feature of the present invention is the provision of a propulsion system for a submarine, which is located at, or towards the bow of the submarine.
Another feature of the present invention is the provision of a propulsion system for a submarine, which uses one or more propellers.
A still further feature of the present invention is the provision of a propulsion system for a submarine, which uses one or more nozzles.
These, as well as other features and advantages of the present invention, will become apparent from the following specification and claims.
The present invention generally comprises a propulsion system for an underwater vehicle, such as a submarine. The propulsion system generally comprises a propeller mounted on a hub which forces water from an inlet out an outlet through a nozzle thereby increasing the water""s velocity and producing a propelling force.
In a preferred embodiment, the present invention includes a nuclear submarine wherein the propulsion system is located at the bow of the submarine. The propulsion system is a propeller-based system. A propeller is housed in a shroud, which is dynamically shaped to provide an airfoil effect and provide an inlet and outlet for water. Water passing through the inlet is accelerated by the propeller and forced into a nozzle region defined by the shroud and the remaining body of the submarine. The inlet to the shroud is covered by a guard, which aids in keeping sea debris from entering the shroud.